Described herein are peptides from secretory phospholipase A2-IB and antibodies that can be used to reduce the contribution of the gastrointestinal tract to inflammatory processes including systemic inflammatory responses. Specifically, antibodies that bind specifically a peptide from secretory phospholipase A2-IB prevent death in a mouse model of LPS-induced endotoxemia. The antibodies described herein are particularly useful to treat systemic inflammatory response syndromes, including sepsis.